Cotton dust exposure results in lung disease among a significant proportion of workers employed in the textile industry. Respiratory illnesses associated with cotton dust exposure include byssinosis (acute and chronic) and chronic bronchitis. Although acute and chronic respiratory disease among cotton textile workers has been recognized for many years, the etiology remains unclear. Recent epidemiological studies suggest that cotton dust may vary in its biological "potency," and one determinant of this "potency" is gram negative bacterial endotoxin. Although exposure-response data are available for cotton spinning workers, there is relatively little epidemiological data on other cotton textile workers engaged in cotton textiles. Since dust controls have already been effected in developed countries, only prospective studies in developing countries can provide information on the factors that influence the progression from acute to chronic cotton dust-induced disease. Such information is important not only for improving our understanding of the disease mechanisms involved in byssinosis, but will also provide useful information in the study of other types of vegetable fiber-induced disease. This proposal is being submitted to obtain resources to analyze prospective data collected on a cohort of Chinese cotton textile workers with modest smoking habits who process medium to fine grade cotton. Data was initially collected in 1981 and consisted of environmental dust and airborne endotoxin assays, respiratory symptoms questionnaire, and pulmonary function tests. A re- survey was conducted in the fall of 1986 with 85% of the original cohort re-tested. The focus of the longitudinal analysis will include a number of fundamental questions that remain unanswered about cotton dust and respiratory disease: (1) Do acute responders go on to develop chronic lung impairment? (2) What prognostic significance does acute byssinosis have in regard to long-term decline in lung function? (3) What happens to acute symptoms when the worker is removed from exposure? (4) What proportion of acute responders leave their job? (5) What is the overall rate of decline in lung function in asymptomatic cotton workers? and (6) Is there a dose-response between cotton dust and endotoxin exposure and decline in lung function? The cohort under study is uniquely suited for epidemiological research aimed at filling the present gaps in our knowledge of the effects of cotton dust exposure.